Press brake

ABSTRACT

THE DISCLOSURE RELATES TO A PRESS BRAKE COMPRISING A FRAME, A BED MOUNTED ON THE FRAME AND A RAM ADAPTED TO MOVE TOWARDS THE BED. MECHANICAL LINKAGES ARE PROVIDED ONE AT EACH END OF THE RAM FOR INTERCONNECTING THE RAM TO THE FRAME OF THE PRESS BRAKE. SUCH MECHANICAL LINKAGES ARE OPERATED SIMULTANEOUSLY TO ENSURE PARALLEL MOVEMENT OF THE RAM TOWARDS THE BED REGARDLESS OF UNEVEN LOADING OF THE PRESS. IN A PREFERRED EMBODIMENT OF THE INVENTION, EACH MECHANICAL LINKAGE COMPRISES A LEVER MEMBER PIVOTALLY MOUNTED ON THE FRAME OF THE PRESS BRAKE AND HAVING ONE END THEREOF CONNECTED TO THE RAM BY MEANS OF TWO LINKS LOCATED ONE ON EACH SIDE OF THE RAM. THE OTHER END OF THE TWO LEVER MEMBERS ARE INTERCONNECTED BY MEANS OF A SUITABLE BAR AND SUCH BAR IS OPERATED BY A SINGLE OPERATING DEVICE. IN ADDITION, AN ADJUSTING WEDGE IS PROVIDED ADJACENT EACH END OF THE BED FOR TILTING THE BED.

United States Patent Rem Fritsch Montreal, Quebec, Canada 21 Appl. No.781,949

[22] Filed Dec. 6,1968

[45] Patented June 28, 1971 [72] Inventor [54] PRESS BRAKE 4 Claims, 6Drawing Figs.

[52] US. Cl 72/389, 72/448, 72/450 [51] Int. Cl 821d 5/01 [50] Field ofSearch... 72/389,

Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. CrosbyAttorneyRaymond A. Robic ABSTRACT: The disclosure relates to a pressbrake comprising a frame, a bed mounted on the frame and a ram adaptedto move towards the bed. Mechanical linkages are provided one at eachend of the ram for interconnecting the ram to the frame of the pressbrake. Such mechanical linkages are operated simultaneously to ensureparallel movement of the ram towards the bed regardless of unevenloading of the press. In a preferred embodiment of the invention, eachmechanical linkage comprises a lever member pivotally mounted on theframe of the press brake and having one end thereof connected to the ramby means of two links located one on each side of the ram. The other endof the two lever members are interconnected by means of a suitable barand such bar is operated by a single operating device. In addition, anadjusting wedge is provided adjacent each end of the bed for tilting thebed.

PATENT ED JUN28 Ian SHEET 2 OF 2 Im==l==ll= Fin. 5

FIG. 5

INVI NrUR Rezso FRITSH A 'I'TURNI'IY PRESS BRAKE This invention relatesto a press brake used in cold forming of sheet metal.

Press brakes are commonly used in the industry for bending sheet metalof various width. They generally comprise a bed for receiving the sheetmetal and a ram which is moved towards the bed for cold forming thesheet metal positioned on the bed. With such machines, it isveryimportant that the movement of the ram be kept parallel to the bed. Thesystems used in the prior art for moving the ram of the press brakestowards the bed usually includes two hydraulic cylinders positioned oneat each end of the ram and interconnected by complicated balancingsystems for ensuring the parallel movement of the ram with respect tothe bed. Such systems, however, are complicated and costly andfurthermore do not ensure a precise parallel movement of the ram.Furthermore, it is also known to provide press brakes with suitableadjustment screws which permit tilting of the ram when it is required todo special fadeout works. However, such threaded adjusting devices arenot always satisfactory as they often jam or deform.

It is therefore the main feature of the invention to provide a pressbrake which ensures an absolutelyprecise parallel movement of the ramwith respect to the bed.

It is also a feature of the invention to provide tilt adjustment of thebed of the press brake instead of the ram thereof to avoid possible jamand to ensure that the ram andram guides remain perfectly aligned.

The press brake, in accordance with the invention, comprises a frame, abed mounted on the frame and a ram adapted to move towards the bed.Mechanical linkages are provided one at each end of the ram forinterconnecting the ram to the frame of the press brake. Such mechanicallinkages are operated simultaneously to ensure parallel movement of theram towards the bed regardless of uneven loading of the press.

In a preferred embodiment of the invention, the mechanical linkages ateach end of the ram comprise a lever member pivotally mounted on theframe of the press brake and having one end thereof connected to the ramby means of two links located one on each side of the ram. The other endof the two lever members are interconnected by means of a suitable barand such bar is operated by a single operating device which may be, forexample, a hydraulic cylinder.

Tilting adjustment of the press brake for accomplishing fadeout works isprovided, in accordance with the invention by adjusting wedges allowingtilting of the bed. Unlike conventional press brakes, the ram is nottilted and, consequently, the ram and ram guides remain always perfectlyaligned.

The invention will now be disclosed with reference to the accompanyingdrawings which illustrate a preferred embodiment of the invention andare not to be taken in a limiting way.

In the drawings:

FIG. 1 is a perspective view illustrating a press brake in accordancewith the invention;

FIG. 2 is a front view of the press brake illustrating more clearly themechanical linkages for operating the ram;

FIG. 3 is a section view of the press brake taken along lines 3-3 ofFIG. 1;

FIG. 4 is a section view of the press brake taken along line 4-4 of FIG.2;

FIG. 5 illustrates the adjusting wedges for tilting the bed; and

FIG. 6 is a front view of the wedge illustrated in FIG. 5.

Referring to FIGS. 1 and 2, there is shown a press brake comprising aframe 10 to which is secured a bed 11 and upon which is mounted a ram 12adapted to move towards bed 11. As commonly known in the art, coldforming of sheet metal is effected by positioning the sheet metalbetween bed 11 and ram 12 and by lowering the ram 12 on the sheet metal.

As mentioned previously, it is necessary to ensure a precise parallelmovement of the ram with respect to the bed in order to effect uniformbending of the sheet metal. In order to ensure parallel movement of theram, there is provided, in accordance with a preferred embodiment of theinvention, two mechanical linkages indicated generally by numeral 13,one at each end of ram 12. Mechanical linkage 13 comprises a levermember 14 pivotally connected by means of pivot 15 to frame 10. Oneendof lever member 14 is connected to ram 12 by means oflinks 16. Theother end of the two lever members 14 are interconnected by a bar 17. Inorder to ensure parallel movement of the ram, it is necessary that thetwo lever members 14 be identical at least as far as the angles anddistances from pivot l5 to the above-mentioned connections to links 16and bar 17 are concerned. Furthermore, the distance between the pivotingpoints of bar 17 on lever members 14 must be equal to the distancebetween the two pivots 15.

Bar 17 is operated by a single operating device such as hydrauliccylinder 18 secured to plates 19 which are in turn welded to frame 10. Apiston 20 is movable within cylinder 17 by conventional hydraulicconnections not shown. Piston 20 is connected to one of lever members 14in the embodiment shown. However, it is to be understood that piston 20may be connected directly to bar 17.

It is also to be understood that other operating devices such aspneumatic cylinders, for example, could be used to activate bar 17.

FIGS. 3 and 4 are section views of FIGS. 1 and 2 illustrating theabove-mentioned elements 10 to 20 from another angle which perhaps willhelp in understanding the invention. In addition, FIG. 3 illustratesgenerally the adjusting wedge 21 which permits the tilting adjustment ofthe bed 11.

FIGS. 5 and 6 illustrate in detail the adjusting wedge designatedgenerally by reference numeral 21 in FIG. 3. Each wedge comprises afirst wedge member 22 having an inclined surface 23 and a'second wedgemember 24 having an inclined surface 25 mating with inclined surface 23.A bracket 26 is secured to wedge member 22 and has a lug 27 integraltherewith for receiving a bolt 28 which is threaded into wedge member24. The tightening of bolt 28 causes the wedge member 24 to slide onwedge member 22 to tilt bed 11. There is one adjusting wedge at each endof the press brake to tilt each end of the bed 11.

The operation of the press brake, in accordance with the invention, maybe more clearly understood with reference to FIG. 2 of the drawings.Movement of bar 17 by hydraulic cylinder 18 in the direction of arrow Acauses rotation of the lever members 14 through an angle B. Because bothlever members 14 are identical as far as the angles and distances frompivot 15 to the pivoting points of links 16 and bar 17 and because thedistance between the pivoting points of bar 17 is equal to the distancebetween pivots 15, links 16 move down a distance in the direction Cwhich is identical at both ends of ram 12. It is therefore seen that themechanical linkages l3 and bar 17 ensures parallel movement of ram 12with respect to bed 11.

I claim:

1. A press brake for use in cold metal working comprising:

a frame;

a bed mounted on said frame;

a ram adapted to move towards said bed;

mechanical linkages located one at each end of said ram forinterconnecting said ram to said frame, said mechanical linkagescomprising a lever member located adjacent each end of said ram andpivotally connected to said frame, two links interconnecting each end ofsaid ram to each lever member, said links being positioned one on eachside of said ram, and a bar interconnecting the other ends of said levermembers;

operating means connected to said bar to pivot said lever memberssimultaneously to ensure parallel movement of said ram towards said bedregardless of uneven loading of the press; and

an adjusting wedge located adjacent each end of the bed for tilting thebed.

2. A press brake as defined in claim I, wherein said operating means isa hydraulic cylinder.

4. A press brake as defined in claim 3, wherein said means for slidingsaid second wedge member on said first wedge member comprises a bracketsecured to said first wedge member and a bolt protruding through saidbracket and threaded to said second wedge member.

